Image forming apparatus using pressing plate and computer-readable medium storing instructions to control movement of pressing plate

Abstract

An electrophotographic image forming apparatus has a controller configured to store a rotation amount of a motor since the tray is attached to a main body of the image forming apparatus as a stored rotation amount, and move, in response to receipt of a print instruction, a pressing plate by driving the motor in the first mode when a remaining rotation amount is equal to or larger than a particular threshold rotation amount, the remaining rotation amount being a difference between a target rotation amount which is a rotation amount necessary to move the pressing plate from a position when the tray is attached to the main body to the conveying position, and the stored rotation amount, or in the second mode when the remaining rotation amount is less than the particular threshold rotation amount.

What is claimed is: 
     
       1. An electrophotographic image forming apparatus comprising:
 a motor; 
 an image forming device configured to form an image on a printing sheet, the image forming device using a driving force transmitted from the motor; 
 a fixing device configure to fix the image formed on the printing sheet; 
 a tray configured to accommodate multiple printing sheets to be conveyed toward the image forming device, the tray being detachably attached to a main body of the image forming apparatus; 
 a pressing plate configured to move up, with use of a driving force of the motor, the printing sheets accommodated in the tray to a conveying position; 
 a storage device; and 
 a controller, 
 wherein the motor is configured to operable in a first mode in which the motor rotates at a first speed and a second mode in which the motor rotate at a second speed which is slower than the first speed, 
 wherein the controller is configured to execute:
 a storing process in which the controller stores a rotation amount of the motor since the tray is attached to the main body as a stored rotation amount; 
 a moving process in which the controller moves, in response to receipt of a print instruction, the pressing plate by driving the motor such that:
 the controller drives the motor in the first mode when a remaining rotation amount is equal to or larger than a particular threshold rotation amount, the remaining rotation amount being a difference between a target rotation amount, which is a rotation amount necessary to move the pressing plate from a position when the tray is attached to the main body to the conveying position, and the stored rotation amount, which is stored in the storage device; and 
 the controller drives the motor in the second mode when the remaining rotation amount is less than the particular threshold rotation amount. 
 
 
 
     
     
       2. The electrophotographic image forming apparatus according to  claim 1 ,
 further comprising a temperature sensor configured to output a temperature signal corresponding to a temperature of the fixing device, 
 wherein the controller is configured to execute:
 a preheating process to apply preheating of the fixing device in response to receipt of the print instruction such that:
 the controller executes a preheating operation for a first time period when the temperature sensor outputs the temperature signal representing that the temperature of the fixing device is equal to or less than the particular threshold temperature; and 
 the controller executes the preheating operation for a second time period which is shorter than the first time period when the temperature sensor outputs the temperature signal representing that the temperature of the fixing device is higher than the particular threshold temperature; and 
 
 the moving process in response to receipt of the print instruction with using the rotation amount when the motor is rotated at the second speed for the first time period as the particular threshold rotation amount when the temperature sensor outputs the temperature signal representing that the temperature of the fixing device is higher than the particular threshold temperature, and 
 
 wherein the controller controls the motor in the first mode when the temperature sensor output the temperature signal representing that the temperature of the fixing device is higher than the particular threshold temperature. 
 
     
     
       3. The electrophotographic image forming apparatus according to  claim 2 ,
 wherein, when the temperature sensor outputs the temperature signal representing that the temperature of the fixing device is equal to or lower than the particular threshold temperature, the controller controls to:
 rotate the motor by the target rotation amount in the first mode; 
 rotate the motor by the particular threshold amount in the second mode, 
 
 wherein, when the temperature sensor outputs the temperature signal representing that the temperature of the fixing device is less than the particular threshold temperature, the controller controls to:
 rotate the motor by a second threshold amount which is a rotation amount of the motor when the motor is rotated at the first speed during the second time period, when the remaining rotation amount is less than the second threshold rotation amount; and 
 rotate the motor by the target rotation amount when the remaining rotation amount is equal to or greater than the second threshold rotation amount. 
 
 
     
     
       4. The electrophotographic image forming apparatus according to  claim 1 ,
 further comprising a tray sensor configured to output a tray sensor signal representing whether the tray is attached to the main body, 
 wherein the controller resets the stored rotation amount of the motor, which is stored in the storage device in response to the tray sensor outputting the tray sensor signal representing that the tray is not attached to the main body. 
 
     
     
       5. The electrophotographic image forming apparatus according to  claim 1 ,
 wherein the image forming device includes:
 a toner accommodator configured to accommodate toner; and 
 an agitator configured to agitate the toner accommodated in the toner accommodator with use of the driving force transmitted from the motor. 
 
 
     
     
       6. The electrophotographic image forming apparatus according to  claim 1 ,
 wherein the controller is configured to execute a counting process to count the number of pulses contained in a pulse signal output by the motor, and 
 wherein the controller is configured to store one of the number of pulses counted in the counting process and the rotation amount of the motor calculated from the number of pulses in the storage device in the storing process. 
 
     
     
       7. The electrophotographic image forming apparatus according to  claim 1 ,
 further comprising a clutch device configured to electrically connect or disconnect transmission of driving force through a drive array which is configured to transmit the driving force of the motor to the pressing plate, 
 wherein the controller is configured to store the rotation amount of the motor when the clutch is connected in the storage device. 
 
     
     
       8. The image forming apparatus according to  claim 1 ,
 further comprising a second tray configured to accommodate the printing sheets to be conveyed to the image forming device, 
 wherein both a roller configured to pick up the printing sheets accommodated in the second tray and a roller configured to pick up the printing sheets accommodated in the tray rotate by the driving force transmitted from the motor, 
 wherein the controller executes the moving process when the print instruction requiring to use the printing sheets stored in the tray is received, while the controller does not execute the moving process when the print instruction requiring to use the printing sheets stored in the second tray is received. 
 
     
     
       9. A non-transitory computer-readable medium storing instructions to be executed by a controller of an electrophotographic image forming apparatus provided with a motor, an image forming device configured to form an image on a printing sheet, the image forming device using a driving force transmitted from the motor, a fixing device configure to fix the image formed on the printing sheet, a tray configured to accommodate multiple printing sheets to be conveyed toward the image forming device, the tray being detachably attached to a main body of the image forming apparatus, a pressing plate configured to move up, with use of a driving force of the motor, the printing sheets accommodated in the tray to a conveying position, a data storage device, wherein the motor is configured to operable in a first mode in which the motor rotates at a first speed and a second mode in which the motor rotate at a second speed which is slower than the first speed,
 the instructions, when executed by the controller, cause the image forming apparatus to execute:
 a storing process in which the controller stores a rotation amount of the motor since the tray is attached to the main body as a stored rotation amount; 
 a moving process in which the controller moves, in response to receipt of a print instruction, the pressing plate by driving the motor such that:
 the controller drives the motor in the first mode when a remaining rotation amount is equal to or larger than a particular threshold rotation amount, the remaining rotation amount being a difference between a target rotation amount, which is a rotation amount necessary to move the pressing plate from a position when the tray is attached to the main body to the conveying position, and the stored rotation amount, which is stored in the data storage device; and 
 the controller drives the motor in the second mode when the remaining rotation amount is less than the particular threshold rotation amount. 
 
 
 
     
     
       10. The non-transitory computer-readable medium according to  claim 9 ,
 wherein the instructions further causes the image forming apparatus to execute:
 a preheating process to apply preheating of the fixing device in response to receipt of the print instruction such that:
 the controller executes a preheating operation for a first time period when a temperature sensor of the fixing device outputs the temperature signal representing that the temperature of the fixing device is equal to or less than the particular threshold temperature; and 
 the controller executes the preheating operation for a second time period which is shorter than the first time period when the temperature sensor outputs the temperature signal representing that the temperature of the fixing device is higher than the particular threshold temperature; and 
 
 the moving process in response to receipt of the print instruction with using the rotation amount when the motor is rotated at the second speed for the first time period as the particular threshold rotation amount when the temperature sensor outputs the temperature signal representing that the temperature of the fixing device is higher than the particular threshold temperature, and 
 
 wherein the controller controls the motor in the first mode when the temperature sensor output the temperature signal representing that the temperature of the fixing device is higher than the particular threshold temperature. 
 
     
     
       11. A method of controlling movement of a pressing plate employed in an electrophotographic image forming apparatus which is provided with a motor, an image forming device configured to form an image on a printing sheet, the image forming device using a driving force transmitted from the motor, a fixing device configure to fix the image formed on the printing sheet, a tray configured to accommodate multiple printing sheets to be conveyed toward the image forming device, the tray being detachably attached to a main body of the image forming apparatus, a pressing plate configured to move up, with use of a driving force of the motor, the printing sheets accommodated in the tray to a conveying position, and a data storage device, the motor being configured to operable in a first mode in which the motor rotates at a first speed and a second mode in which the motor rotate at a second speed which is slower than the first speed,
 wherein the method comprises:
 a storing step to store a rotation amount of the motor since the tray is attached to the main body as a stored rotation amount; 
 a moving step to move, in response to receipt of a print instruction, the pressing plate by driving the motor:
 in the first mode when a remaining rotation amount is equal to or larger than a particular threshold rotation amount, the remaining rotation amount being a difference between a target rotation amount, which is a rotation amount necessary to move the pressing plate from a position when the tray is attached to the main body to the conveying position, and the stored rotation amount, which is stored in the storage device; and 
 in the second mode when the remaining rotation amount is less than the particular threshold rotation amount. 
 
 
 
     
     
       12. The method according to  claim 11 ,
 wherein the method further comprises:
 a preheating step to apply preheating of the fixing device in response to receipt of the print instruction such that:
 a preheating operation is executed for a first time period when the temperature sensor, which is configured to output a temperature signal corresponding to a temperature of the fixing device, outputs the temperature signal representing that the temperature of the fixing device is equal to or less than the particular threshold temperature; and 
 the preheating operation is executed for a second time period which is shorter than the first time period when the temperature sensor outputs the temperature signal representing that the temperature of the fixing device is higher than the particular threshold temperature, 
 
 
 wherein the method executes the moving step in response to receipt of the print instruction with using the rotation amount when the motor is rotated at the second speed for the first time period as the particular threshold rotation amount when the temperature sensor outputs the temperature signal representing that the temperature of the fixing device is higher than the particular threshold temperature, and 
 wherein the motor is controlled to operate in the first mode when the temperature sensor output the temperature signal representing that the temperature of the fixing device is higher than the particular threshold temperature.